Xenotransplantation: a summary of the International Business Communications' Fourth International Congress

Liver transplantation. Living donor, hepatocyte, and xenotransplantation

Liver transplantation is now accepted as effective therapy in the treatment of acute and chronic hepatic failure. Improvements in surgical techniques and immune suppression have led to 5-year survival rates that exceed 70% in most centers. The success of transplantation has led to a dramatic increase in the number of candidates to over 14,000 places on the national waiting list. While the number of patients in need of transplantation increases, there has been little growth in the supply of available cadaveric organs, resulting in an organ shortage crisis. With waiting times often exceeding 1 to 2 years, the waiting list mortality now exceeds 10% in most regions. Several novel approaches have been developed to address the growing disparity between the limited supply and excessive demand for suitable organs.

Which hepatocyte will it be? Hepatocyte choice for bioartificial liver support systems

Liver failure, notwithstanding advances in medical management, remains a cause of considerable morbidity and mortality in the developed world. Although bioartificial liver (BAL) support systems offer the potential of significant therapeutic benefit for such patients, many issues relating to their use are still to be resolved. In this review, these issues are examined in terms of the functions required, the cells of choice in such a system, and the most appropriate environment to optimize the function of such cells. The major functions identified to date for a BAL are ammonia detoxification and biotransformation of toxic compounds, although this somewhat belies the complexity of the functions required. Two practical choices for cell type within such a system are xenogenic hepatocytes and immortalized human hepatocyte lines. Both these choices have drawbacks, such as the transmission of zoonoses and malignant infiltration, respectively. Finally, improvements in culture conditions, such as supplemented media, biodegradable scaffolds, and coculture, offer the possibility of prolonging the differentiated function of hepatocytes in a BAL.